This year’s Ohio Maple Days welcomed back the free hydrometer testing service that folks had come to expect from Dr. Gary Graham’s days of leading the annual Ohio maple event.

As part of the tri-state (OH – WV – PA) ACER grant, we built out at least 1 full hydrometer testing kit for each state to ensure accurate hydrometers are in the hands of maple producers in order to produce top-quality maple syrup.  A big thanks to Carri Jagger for leading the charge on this initiative, we figured that she and I tested somewhere in the neighborhood of 75-90 hydrometers during Saturday’s program.  These are rough estimates, but I would guess around half the hydrometers tested within +/- 0.2 Brix of perfect.  1 out of every 10 hydrometers read heavier densities than they should have, and the remainder – close to 3 or 4 out of every 10 – read light compared to the standard.

For a bit more complete explanation and how to make sense of the Hydrometer Testing Bookmarks, let’s explore a couple scenarios.

The first scenario is that your hydrometer reads the exact same as our standard testing hydrometer.  This bookmark shows a best case scenario and this is exactly what that means.  We chose to test everyone’s hydrometer against a test solution of 60.0 Brix.  In other words, we mixed a test solution to read 60.0 Brix on our standard hydrometer and checked everyone else’s instrument against the truth of that standard.  Choosing 60.0 Brix as the test line is somewhat arbitrary, we could have chosen 62.0 or 64.0 or 65.7 if we were really feeling inspired.  The bottom line is that within a certain range, an inch is an inch, and if your ruler is really truly measuring 24″ where it says 24″, the same ruler should also be spot on when measuring something 30″ long as well.  The same concept applies here.  Known density is 60.0, your hydrometer reads 60.0, and your glass, paper scale, and hydrometer is in great condition.

Heavy Syrup LLC and Wimpy Syrup & Co. are both less than ideal hydrometer testing scenarios.

Wimpy Syrup & Co.’s hydrometer is reading heavy even though their hydrometer is in good condition from a wear and tear perspective.  The effect of having a hydrometer that reads heavy is that you’ll likely be producing syrup on the underside of optimal density.  In other words, you’ll pull your syrup off early because of the heavy reading and may not finish all the way up at the perfection standard of 66.9 Brix.

Heavy Syrup LLC has the opposite issue.  Because their hydrometer is reading light, syrup will probably get left on the evaporator a tad long and finish at a higher density than the industry standard.  Hence, we can see that the directional error in hydrometer reading leads to syrup that finishes in the opposite direction.  A heavier reading than truth leads to lighter syrup. Lighter readings lead to heavier syrup.  The additional issue with Heavy Syrup LLC’s hydrometer is that the paper scale has become twisted, likely as a result of a glue dot detaching, eliminating any hope of accurate density readings in the future.  Throw that hydrometer away.

Hopefully this post sheds some light on why hydrometer testing is important.  A big thanks to all the producers who brought one or two or five hydrometers to be tested.  We will plan to offer the same service at Ohio Maple Days going forward and add a second testing beaker for sap hydrometers at next year’s event.  Syrup density is one of the key diagnostics to ensure we produce quality maple syrup and accurately reading density is an important skill as a sugarmaker.  If you have a hydrometer that you know is off, toss it in the garbage and ask Santa to put another in your stocking ASAP.